Many types of hardware are available both for the fixation of bones that are fractured and for the fixation of bones that are to be fused (arthrodesed).
For example, the human hip girdle is made up of three large bones joined by three relatively immobile joints. One of the bones is called the sacrum and it lies at the bottom of the lumbar spine, where it connects with the L5 vertebra. The other two bones are commonly called “hip bones” and are technically referred to as the right ilium and-the left ilium. The sacrum connects with both hip bones at the sacroiliac joint (in shorthand, the SI-Joint).
The SI-Joint functions in the transmission of forces from the spine to the lower extremities, and vice-versa. The SI-Joint has been described as a pain generator for up to 22% of lower back pain.
To relieve pain generated from the SI Joint, sacroiliac joint fusion is typically indicated as surgical treatment, e.g., for degenerative sacroiliitis, inflammatory sacroiliitis, iatrogenic instability of the sacroiliac joint, osteitis condensans ilii, or traumatic fracture dislocation of the pelvis. Currently, screws and screws with plates are used for sacro-iliac fusion.
In order to promote bone growth into the implant and enhance fusion of the implant with the bone, pockets or channels can be created in the implant that promote bone growth into the implant. However, these pockets or channels may weaken the structural integrity of the implant, which can also be required to bear large stresses. Therefore, it would be desirable to provide an implant with pockets or channels to promote bone growth while substantially maintaining the structural integrity of the implant.